This automatically overlaps all muffin-tins to a specified
maximum value (default folpx=1.15) to reduce the effects of
potential discontinuities at the muffin-tins. Automatic overlapping
is done by default and is useful in highly inhomogeneous materials.
Typical values of the overlapping fraction should be between 1.0 and
1.3. See FOLP for a non-automated version.
Automatic overlapping is done by default; to switch overlapping off,
use 1.0 as the argument for AFOLP.
* touching muffin-tins; do not use automatic overlapping